Incidentally, D-Wave has posted some details of their implementation on the arxiv. I have only had a chance to skim it so far, but I was amused to see that their readout scheme couples their qubits to an LC circuit, and they measure the phase shift of the resonator. This is an idea which has become increasingly popular after my lab demonstrated it in 2003 (Patrice Bertet published results for an harmonic oscillator readout of their flux qubits, and I understand that John Martinis' group has now coupled their phase qubits to a resonator).